1. Field of the Invention
The present invention relates to a door lock switch assembly in a drum type washing machine, and more particularly, to a door lock switch assembly which has a simple structure and an improved operation reliability in locking and unlocking a door.
2. Background of the Related Art
In general, the drum type washing machine washes laundry by using friction between a drum rotated by a driving force from a motor and laundry under a state detergent, washing water, and the laundry are introduced in the drum. The drum type washing machine has advantages in that the laundry is almost not involved in damage and tangling between the laundry, and in that washing effects obtainable by beating and rubbing the laundry can be provided.
A related art drum type washing machine will be explained with reference to FIGS. 1xcx9c5. FIG. 1 illustrates an outside view of a related art drum type washing machine. Referring to FIG. 1, a tub, a water storage tank, is provided inside of a body 13, and a drum 14 is fixed at a center of the tub to be rotated by the driving motor. The drum type washing machine has a door at the front of the body 13, for introducing and taking out the laundry. And, since the detergent, washing water and laundry will gush out of the door 15 to make a floor dirty if the door 15 is opened in the middle of washing unintentionally, the related art drum type washing machine has a door lock for preventing the unintentional opening of the door 15 before it happens. The door lock has a door lock switch assembly on an inside of a front side of the body 13, and a latch 16 at a front end of an opposite side of a hinge of the door 15.
Meanwhile, as shown in FIG. 2 to FIG. 5, the related art door lock switch assembly is provided with a switch case 100, a switch cover 200 fitted to the switch case 100, a latch holder 300, a slide 400, a solenoid assembly, a switching terminal, and an operating lever 17. The latch holder 300 is rotatably fitted to the front of the switch case 100 to exert a restoring force in door unlocking direction, wherein a left side on the drawing is referred to the front and a right side thereon is referred to the rear in FIG. 2 to FIG. 4c. The slide 400 is fitted to the rear of the latch holder 300 in a state tilted at an angle to enable forward and backward movement perpendicular to an axis direction of the latch holder 300. The solenoid assembly has a plunger 6 press fitted inside of a clamp part 100a in a central portion of the switch case 100 for being drawn into a solenoid 5 to retract the slide 400 in a right direction on the drawing when the solenoid 5 is turned on. The solenoid assembly further has a compression spring 7 fitted to an outer circumference of the plunger 6 to push the plunger forward. The switching terminal has xe2x80x98xe2x80x99 or xe2x80x98xe2x80x99 shape, and is fitted to the rear of the switch cover 200 to place a contact point at a side of the solenoid assembly. The operating lever 17 is hinge-coupled to a lower side of the switch cover 200 to unlock the door by manual backward moving of the slide 400.
The slide 400 has a plurality of stoppers (i.e., a first stopper 400a, a second stopper 400b and a third stopper 400c) at its sloped front, for arresting the latch holder 300 to prevent the latch holder 300 from returning to its original position when the door is locked. The latch holder 300 has a plurality of projections (i.e., a first projection 300a. a second projection 300b. and a third projection 300c) at its front end, for positioning the stoppers when the door is locked, respectively. The latch holder 300 has slots 300d and 300e between the first projection 300a and the third projection 300c of the front end of the latch holder 300, for avoiding, interference with the second stopper 400b and the third stopper 400c on the slide 400 when the latch holder 300 is rotated by a pushing force of the latch 16 as the door 15 is closed, and a slot 300f below the second projection 300b just below the upper slot 300d (an upper part on the drawing is referred to as an upper direction) for fitting to the second stopper 400b on the slide 400 when the door is locked. The latch holder 300 also has a sloped projection 300g at a top of the front end thereof, for pushing the slide 400 upward to tilt the slide 400 in a horizontal direction, to open a contact point of the switch in a door opening, and the slide 400 has a sloped projection 400e at a top of the first stopper 400a as a unit with the first stopper 400a, for being pushed by the sloped projection 300g on the latch holder 300 in an door opening, to tilt the slide 400 in the horizontal direction. That is to say, the latch holder 300 is provided with the sloped projection 300g, the first projection 300a, the upper slot 300d, the second projection 300b with the slot 300f, the lower slot 300e, and the third projection 300c formed at the front end thereof from the top to the bottom, and the slide 400 is provided with the sloped projection 400e, the first stopper 400a, the second stopper 400b, and the third stopper 400b formed at the front end thereof from the top to the bottom.
Meanwhile, there is a compression spring 18 between one point of an upper sidewall 400f of the slide 400 and one point at the rear of the switch case 100 higher than the one point of the upper sidewall 400f, for pressing the upper sidewall 400f of the slide 400 downward on the drawing when the slide 400 moves forward in a door locking to bring the slide 400 into a horizontal posture. The slide 400 also has a pad 400g below the upper sidewall 400f of the slide 400, for pushing a movable contact 800 to isolate from a fixed contact 900 as the slide 400 is tilted when the door lock is released.
The operating lever 17 has a knob 170 for latching a strap 12, a plurality of resilient pieces 171, and a push rod 173. When the strap 12 is pulled, the plurality of resilient pieces 171 are deformed as the resilient pieces are brought into contact with an outer surface of the switch case 100. If a force pulling the strap 12 is removed, the resilient pieces 171 return the operating lever 17 to its original position. As the resilient pieces 171 are deformed by the force applied to the strap 12, the push rod 173 rotates around a hinge shaft 172 and pushes one side of the slide 400 to the rear.
The operation of the aforementioned related art door lock switch assembly will be described. First, a door locking operation from a state the door 15 is opened will be described with reference to FIG. 1 to FIG. 2b. 
In the door opened state as shown in FIG. 1, the door lock switch assembly is in a state as shown in FIG. 2a. That is to say, in the door opened state, the slide 400 is pushed upward by the sloped projection 300g at the top of the front end of the latch holder 300, so that the slide 400 is in a state tilted at an angle xcex8 with respect to the horizontal direction as shown in FIG. 2a. In the state the door is opened thus, if the door is closed by rotating the door around the hinge shaft, the latch 16 at the front end of the door pushes the latch holder 300, so that the latch holder 300 is rotated around the hinge shaft 210 as a torsion spring 19 is deformed, elastically. As the latch holder 300 rotates thus, the sloped projection 300g at the top of the front end of the latch holder 300 slides along a surface of the sloped projection 400e of the slide 400. In this instance, as the sloped projection 300g leaves away from the sloped projection 400e gradually, the slide 400 moves in a direction the slide 400 takes a horizontal posture as the compression spring 7 pushes the upper sidewall 400f of the slide 400. At the same time, the second stopper 400b and the third stopper 400b projected forward from the sloped side 400d in the front end of the slide 400 move into the slots 300d and 300e at the front end of the latch holder 300. Then, the latch holder 300 continues rotation until a moment the slide 400 reaches to a position where interferences between the front end of the latch holder 300 and the stoppers on the slide 400 cease to exist when the slide 400 advances toward the latch holder 300 as the plunger 6 pushes the slide 400. That is to say, at the moment that interferences between the front end of the latch holder 300 and the projections on the slide 400 cease to exist, the plunger 6 advances forward by restoring force of the compression spring 7 provided on the outer surface of the plunger 6, and the slide 400 advances toward the latch holder 300 as the plunger 6 pushes the slide 400. As a result, the projections 300a, 300b and 300c and the slot 300f are brought into contact with the stoppers 400a, 400b and 400c on the slide 400, as shown in FIG. 2b. In this instance, the latch holder 300 can not return to a position where the door lock is released even though the pushing force of the latch holder 300 is eliminated as the latch holder 300 is caught by the slide 400. Under this circumstances, the latch 16 at the front end of the door 15 is located in a hook 3a in the latch holder 300 so that the latch 16 is subjected to a restraint of the hook 3a. Consequently, the door can not be opened. On the other hand, under a door locked state, i.e., in a state that the slide 400 advances to the maximum as the plunger 6 pushes the slides, with their axes positioned on the same horizontal line without any slope, the position of the movable contact 800 of the switching terminals is varied with the position of the upper sidewall 400f, to bring the movable contact 800 into contact with the fixed contact 900 to turn on the switch, to provide a power to the driving part, a water supply valve, and a water discharge pump (not shown) in the drum type washing machine.
A process for automatic unlocking of the door in a case a door lock release button is pressed to provide a power to the solenoid assembly in a door locked state will be described with reference to FIG. 2b. and FIGS. 3a to FIG. 3c. 
As shown in FIG. 2b, the contact point is in a closed state in a door locked state, to allow the power provided to the solenoid assembly. If the user pushes a door lock release button(not shown), the power is provided to the solenoid 5. Then, the plunger 6 compresses a coil spring around the plunger 6 as the solenoid 5 draws the plunger 6, and moves away from the latch holder 300. In this instance, the plunger 6 moving away from the latch holder 300 allows the slide 400 pushed in the same direction, such that the respective stoppers 400a, 400b and 400c on the slide 400 in contact with the projections 300a, 300b and 300c and the slot 300f to hold rotation of the latch holder 300 escape from the projections 300a, 300b and 300c and the slot 300f at a certain moment. At the moment the respective stoppers 400a, 400b and 400c escape from the projections 300a, 300b and 300c and the slot 300f, the latch holder 300 returns to the door opened state by restoring force of the torsion spring 11. In other words, as shown in FIG. 3a, at a door lock release by the solenoid assembly, the plunger 6 is retracted to come into contact with a rear wall of the slide 400, and push the slide 400 backward, until the latch holder 300 passes through a state in FIG. 3b in which the latch holder 300 is about to escape from an interference of the slide 400 when the latch holder 300 is released from the restraint of the slide 400, such that the latch holder 300 is rotated by the restoring force of the torsion spring 11, to open the door. In a word, the slide 400 is pushed backward by the plunger 6 when the plunger 6 moves backward according to action of the solenoid 5 until the slide 400 and the latch holder 300 are freed from the interference completely, when the latch holder 300 returns to the door opened position, to release the latch 16 from the hook 3a of the latch holder 300, thereby unlocking the door.
Meanwhile, in the aforementioned door unlocking operation, the slide 400 is pushed upward by the sloped projection 300g at the top of the front end of the latch holder 300 at the moment the slide 400 is released from the latch holder 300, when the slide 400 is tilted at an angle xcex8 with respect to the horizontal line as shown in FIG. 3c in the same manner as that of FIG. 2a. In this door lock release, as the slide 400 is pushed upward by the sloped projection 300a, the movable contact 800 in contact with the fixed contact 900 is moved away from the fixed contact 900 as the pad 400g on the slide 400 pushes the movable contact 800, so that the contact points between the fixed contact 900 and the movable contact 800 are opened. As the contact points between the fixed contact 900 and the movable contact 800 are thus opened, no power can be provided to the driving part, the water supply valve and the water discharge pump in the washing machine.
Different from the foregoing operation, there may be a case when it is required to release the door lock in a state the power to the washing machine is cut off due to power failure or disorder thereof, when a cover 20 at one side of a lower part of front of the drum type washing machine is opened and the strap 12 inside of the cover 20 is pulled, to activate the door lock switch assembly for releasing the door lock manually, which operation will be described with reference to FIG. 4a to FIG. 4c. As shown in FIG. 4a, in the state that the door is locked, when the strap 12 is pulled by the user, the operating lever 17 is rotated around the hinge shaft 172 in a clockwise direction on the drawing, when the push rod 173 formed as a unit with the operating lever 17 pushes the slide 400 backward until the interference between the slide 400 and the latch holder 300 is released as shown in FIG. 4b, when the latch holder 300 returns to its original position by restoring force of the torsion spring 19, thereby unlocking the door as shown in FIG. 4c. Meanwhile, if the force is applied to the operating lever 17 no more after the door is unlocked, the operating lever 17 returns to its original position, because ends of the resilient pieces 171 extended from the hinge of the operating lever are in contact with the lower side of the switch case 100.
However, the related art door lock switch assembly has the following problems in view of structure and a reliability of operation.
First, the construction of interference and interference release between the latch holder 300 and the slide 400 to unlock the door is complicate. In other words, the slide 400 is required to be provided with the plurality of stoppers 400a, 400b and 400c at its front for stopping the latch holder 300, and the sloped projection 400e having the sloped side for positioning an axis of the slide 400 on the same line with an axis of the plunger 6 in a door locking, and positioning the axis of the slide 400 tilted at an angle with respect to the axis of the plunger 6 in a door locking release.(see FIG. 5). The compression spring 18 provided between one point of the upper sidewall 400f of the slide 400 and one point at the rear of the switch case 100 presses the upper sidewall 400f downward on the drawing when the slide 400 advances to lock the door. In this instance, since direction of a pressing force of the compression spring 18 is not coincident with its axis, transmission of the pressing force is not effective. In addition to this, the latch holder 300 is required to be provided with the plurality of projections 300a, 300b and 300c and the slot 300f for being caught at the stoppers 400a, 400b and 400c at the front portion of the slide 400 in a door locking, and the sloped projection 300g at the top thereof to press the sloped projection 400e upward to displace the slide 400, that turns off the switch. (see FIG. 5).
Second, since the related art door lock switch assembly has a complicated switching operation system, an operation system of the movable contact 800 and the fixed contact 900 is also complicate. In other words, the switching operation system of the movable contact 800 and fixed contact 900 is complicate since a direction of the switching operation of the movable contact 800 and fixed contact 900 is conducted, not coincident with the axis of the plunger 6, but perpendicular to the axis of the plunger, and has a very complicate terminal fastening construction in the switch case since the contact point is located on a side of the solenoid 5 and a power supply terminal is located in the rear end of the switch case, that requires the terminal to be very long and L bent. And, to open the contacts between the movable contact 800 and the fixed contact 900 in the event the slide 400 moves backward, the switching operation system of the movable contact 800 and fixed contact 900 is required to be provided with the pad 400g for directly pressing, and displacing the movable contact 800 because the switching action is made perpendicular to the axis of the plunger 6. Accordingly, the fastening structure of the movable contact 800 and the fixed contact 900 provided in the switch case 100 also becomes very complicate, and the structure of the latch holder and the slide becomes complicate, thereby deteriorating component fabrication and assembly. Furthermore, the lengthy terminals of the movable contact 800 and the fixed contact 900 pushes cost up.
Third, the related art door lock switch assembly requires a large force for operation of the operating lever when the door 15 is unlocked manually from a door locked state since a pulling force is exerted indirectly in making a rotation centered on a hinge shaft of the operating lever 17. In other words, the operating force applied to the strap 12 is transferred to the slide 400, not directly, but only when the resilient pieces 171, which are formed as a unit with the operating lever and has fore ends in contact with the bottom of the switch case 100, are deformed, when the end of the push rod 173 is made to push the slide 400. In particular, as deformation of the resilient pieces becomes the greater, resisting power of the resilient pieces becomes the greater, the pulling force on the strap 12 is required to be the greater until the door is unlocked.
As described, the related art door lock switch assembly has problems in that the operation system for locking and unlocking the door is complicate and, consequently, structures of individual components are also complicate, thereby causing difficulty in shaping molds and the followed process, and in assembly, and an operation reliability is deteriorated.
Accordingly, the present invention is directed to a door lock switch assembly in a drum type washing machine that substantially obviates one or more of the problems due to limitations and disadvantages of the related art.
An object of the present invention is to provide a door lock switch assembly in a drum type washing machine which has a simple structure and an improved operation reliability when locking and unlocking a door.
Additional features and advantages of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.
To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described, the door lock switch assembly in a drum type washing machine includes a switch case, a switch cover fitted to the switch case, a latch holder rotatably, and elastically mounted in one side portion of the switch case for exerting a restoring force in a door open direction, a slide fitted to one side of the latch holder, for moving up or down in a direction the same with a hinge shaft of the latch holder to arrest or release the latch holder, a solenoid assembly mounted in a central portion of the switch case, for moving up or down the slide, and a switching part located below the slide, for making a switching operation as a terminal thereof makes a seesaw action following the moving up or down of the slide.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.